Let me take issue with one point (most of the rest I'm uninformed about):
Relational databases aren't particularly compact. What they are is
generalizable...and even there...
The most general compact database is a directed graph. Unfortunately,
writing queries for retrieval requires domain kno
But how much information is in a map, and how much in the relationship
database? Presumably you can put some v. rough figures on that for a given
country or area. And the directions presumably cover journeys on roads? Or
walks in any direction and between any spots too?
All of the information
